case 3: cout << "按作者名查找图书信息\n" << endl; cout << "请输入要查询的作者名字："; cin >> book_author; // 修正变量名 query = "select * from books where author = '" + book_author + "'"; if (mysql_query(&mysql, query.c_str())) { cout << "Error: Query[查询成功] fail." << mysql_error(&mysql)<<endl; break; } res = mysql_store_result(&mysql); row = mysql_fetch_row(res); if (row) { // 判断查询结果是否为空 cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << endl; } else { cout << "未找到相关图书信息" << endl; } break; } break;运行后为什么没有出现图书信息而是输出Error: Query[查询成功] fail.Unknown column 'author' in 'where clause'

case 3: cout << "按作者名查找图书信息\n" << endl; cout << "请输入要查询的作者名字："; cin >> book_author; // 修正变量名 query = "select * from books where author = '" + book_author + "'"; if (mysql_query(&mysql, query.c_str())) { cout << "Error: Query[查询成功] fail." << endl; break; } res = mysql_store_result(&mysql); row = mysql_fetch_row(res); if (row) { // 判断查询结果是否为空 cout << "编号: " << row[0] << " 书名: " << row[1] << " 当前数量: " << row[2] << " 价格:￥" << row[3] << " 作者:" << row[4] << endl; } else { cout << "未找到相关图书信息" << endl; } break; } break;运行后为什么没有出现图书信息而是输出Error: Query[查询成功] fail.

根据代码，出现"Error: Query[查询成功] fail."的原因可能是mysql_query()函数执行失败导致的。这可能是由于MySQL连接出现问题、查询语句错误或者权限不足导致的。您可以尝试检查以下几个方面： 1. 检查MySQL连接...

#include <iostream> using namespace std; #include <stdio.h> int main() { int sc[6]={500, 100, 50, 10, 5, 1}; // 6种零钞的面值 int num[6]={0}; // 存储找零最优方案，即6种零钞的数目 float m; int mint; // 存放当前零钱面值总额 int i; freopen("ChangeNote.in", "r", stdin); freopen("ChangeNote.out", "w", stdout); cin>>m; // 输入零钱金额 //************************************************ for(i=0; i<6; i++) { num[i]=m/sc[i]; m=m-sc[i]*num[i]; } //================================================= for(i=0; i<6; i++) if(num[i]!=0) switch(i) { case 0: cout<<" 伍圆: "<<num[0]<<endl; break; case 1: cout<<" 壹圆: "<<num[1]<<endl; break; case 2: cout<<" 伍角: "<<num[2]<<endl; break; case 3: cout<<" 壹角: "<<num[3]<<endl; break; case 4: cout<<" 伍分: "<<num[4]<<endl; break; default: cout<<" 壹分: "<<num[5]<<endl; } return 0; }补全

case 3: cout<<" 壹角: "<<num[3]<<endl; break; case 4: cout<<" 伍分: "<<num[4]<<endl; break; default: cout<<" 壹分: "<<num[5]<<endl; } return 0; } 其中，freopen 函数用于将标准输入输出...

cout<<"Case #"<<(i+1)<<": false"<<endl;

这段代码的意思是输出"Case #"，然后接着输出i+1，再输出": false"，最后换行输出。所以这段代码的输出结果...1234

std::cout << "输入起点城市：" << endl; cin >> start; std::cout << "输入终点城市：" << endl; cin >> end; for (int i = 0; i < graph.vexnum; i++) { if (cities[i].city == start) s = i; if (cities[i].city == end) e = i; } //最短路径 system("cls"); std::cout << "读取完成" << endl; std::cout << "请选择最短路径要求" << endl; std::cout << "时间：1 " << endl; std::cout << "价格：2 " << endl; cin >> p; system("cls"); switch (p) { case 1: std::cout << "以时间为基准：" << endl; TimeShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "时间：" << D[e] << " h "; TxtWriting(graph, c, n); break; case 2: std::cout << "以价格为基准：" << endl; CostShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "价格：$" << D[e]; TxtWriting(graph, c, n); break; } return 0; } //构造控制台

1. 通过 std::cout 输出提示信息，让用户输入起点城市和终点城市。 2. 通过循环遍历 cities 数组，找到起点城市和终点城市在数组中的下标。 3. 通过 switch 语句让用户选择最短路径的要求，即以时间为基准还是以价格...

int main() { int choice; do { loginMenu(); cin >> choice; switch (choice) { case 1: // 学生登录 loginUser(); break; case 2: // 管理员登录 adminLogin(); break; case 3: cout << "注册" << endl; registerUser(); break; case 0: // 退出 break; default: cout << "无效的选择，请重新输入！" << endl; break; } while (choice != 0); return 0; } }怎么修改

这段代码有一个缺少右括号的错误，需要在 switch 语句后面添加一个右括号。另外，while 循环应该放在 do ... cout << "无效的选择，请重新输入！" << endl; break; } } while (choice != 0); return 0; }

} int main() { int choice; do { loginMenu(); cin >> choice; switch (choice) { case 1: // 学生登录 loginUser(); break; case 2: // 管理员登录 adminLogin(); break; case 3: cout << "注册" << endl; registerUser(); break; case 0: // 退出 break; default: cout << "无效的选择，请重新输入！" << endl; break; } while (choice != 0); return 0; } }

您的代码有一个错误，缺少一个右括号来关闭do-while循环。... default: cout << "无效的选择，请重新输入！" << endl; break; } } while (choice != 0); return 0; } 这样就可以正确编译和执行您的代码了。

system("cls"); std::cout << "读取完成" << endl; std::cout << "请选择最短路径要求" << endl; std::cout << "时间：1 " << endl; std::cout << "价格：2 " << endl; cin >> p; system("cls"); switch (p) { case 1: std::cout << "以时间为基准：" << endl; TimeShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "时间：" << D[e] << " h "; TxtWriting(graph, c, n); case 2: std::cout << "以价格为基准：" << endl; CostShortPath(graph, s, way, D); for (int i = 0; i < 199; ++i) { if (way[e][i] == n) { c[n - 1] = i; std::cout << cities[i].city << ' '; n++; i = -1; } } std::cout << std::endl; std::cout << "价格：$" << D[e]; TxtWriting(graph, c, n); }

这段代码实现了一个简单的控制台界面，让用户输入最短路径的要求（时间或价格），并调用相应的函数求解最短路径，并输出路径信息和路径花费。具体来说，该代码先清空控制台屏幕，然后输出提示信息，让用户选择最短...

#include <iostream> #include <stdio.h> #include <stdlib.h> #include <string.h> using namespace std; class a{ public: char mingzi; int xuehao; a next; void set_mingzi(char name) { mingzi=name; } void set_xuehao(int number) { xuehao=number; } void show_mingzi() { cout << mingzi <<'\n'; } void show_xuehao() { cout << xuehao; } }; void luru(){ } void menu () { bool panduan = 1; while (panduan=1){ cout << "请选择" <<'\n'; cout << "1.录入学生的校园消费信息"<<'\n'; cout << "2.修改某个学生的某次校园消费信息"<<'\n'; cout << "3.查询某个学生的校园消费情况"<<'\n'; cout << "4.删除某个学生的某次校园消费信息"<<'\n'; cout << "5.统计某段时间内，进行校园消费的学生姓名及消费金额，按消费金额由多到少排序"<<'\n'; cout << "6.按消费类型分类，统计某段时间内，在每种消费类型上学生的消费总额"<<'\n'; char x; cin >> x; //system("cls"); switch(x){ case'1': cout << "录入学生的校园消费信息"<<'\n'; luru(); break; case'2': cout << "修改某个学生的某次校园消费信息"<<'\n'; break; case'3' : cout << "查询某个学生的校园消费情况"<<'\n'; break; case'4' : cout << "查询某个学生的校园消费情况"<<'\n'; break; case'5' : cout << "查询某个学生的校园消费情况"<<'\n'; case'6' : cout << "查询某个学生的校园消费情况"<<'\n'; break; default: cout << "输入非法，请重新选择!"; break; } } cout <<"谢谢使用"; } int main() { ahead = NULL; a*p= NULL; menu(); };为我的代码添加链表

cout << "请输入学生姓名：" << endl; cin >> p->mingzi; cout << "请输入学生学号：" << endl; cin >> p->xuehao; p->next = head; // 新的节点指向当前头节点 head = p; // 更新头节点 cout << "学生信息...

int main() { int choice; do { cout << "1.增加人员信息" << endl; cout << "2.删除人员信息" << endl; cout << "3.修改人员信息" << endl; cout << "4.查找人员信息" << endl; cout << "5.保存人员信息" << endl; cout << "6.读取人员信息" << endl; cout << "0.退出系统" << endl; cout << "请输入你的choice" << endl; cin >> choice; switch (choice) { switch (choice) { case 1: { string id, name, dept, grade, group, pos; cout << "Enter student ID: "; cin >> id; cout << "Enter name: "; cin >> name; cout << "Enter department: "; cin >> dept; cout << "Enter grade: "; cin >> grade; cout << "Enter group: "; cin >> group; cout << "Enter position: "; cin >> pos; Member member(id, name, dept, grade, group, pos); team.addMember(member); cout << "Member added successfully." << endl; break; } case 2: { string id; cout << "Enter student ID to delete: "; cin >> id; team.deleteMember(id); cout << "Member deleted successfully." << endl; break; } case 3: { string id, group, position; cout << "Enter student ID to modify: "; cin >> id; cout << "Enter new group: "; cin >> group; cout << "Enter new position: "; cin >> position; team.modifyMember(id, group, position); cout << "Member modified successfully." << endl; break; } case 4: team.displayMembers(); break; case 5: team.saveToFile(); break; case 0: cout << "Exiting program." << endl; break; default: cout << "Invalid choice. Please try again." << endl; break; } } while (choice != 0); return 0; } 这段代码错误该怎么改

cout << "请输入你的choice: "; cin >> choice; switch (choice) { case 1: { string id, name, dept, grade, group, pos; cout << "Enter student ID: "; cin >> id; cout << "Enter name: "; cin >> ...

#include <iostream> #include <string> #include <functional> int main() { std::string input = "hello"; std::size_t hash = std::hash<std::string>{}(input); switch (hash) { case std::hash<std::string>{}("hello"): std::cout << "You entered 'hello'" << std::endl; break; case std::hash<std::string>{}("world"): std::cout << "You entered 'world'" << std::endl; break; default: std::cout << "You entered something else" << std::endl; break; } return 0; }

具体而言，它首先定义了一个字符串变量 input，然后使用 std::hash<std::string>{}(input) 来计算 input 的哈希值，并将结果存储在 hash 变量中。接着使用 switch 语句来根据哈希值进行条件判断，如果哈希值等于 ...

The following is an attempt to create a class to represent information about pets: class Pet { public: Pet(); void printDescription(); string name; int type; bool neuterSpayed; bool talks; }; Pet::Pet() : type(0), neuterSpayed(false), talks(false) { } void Pet::printDescription() { switch (type) { case 0: cout << "Dog named " << name << endl; cout << "Neuter/Spayed: " << neuterSpayed; break; case 1: cout << "Cat named " << name << endl; cout << "Neuter/Spayed: " << neuterSpayed; break; case 2: cout << "Bird named " << name << endl; cout << "Talks: " << talks << endl; break; } cout << endl; } Rewrite this code using inheritance. You should have a Pet class with subclasses for Dog, Cat, and Bird. Variables should be associated with the appropriate classes, defined as private when appropriate, and have appropriate functions to access the variables. Rewrite the printDescription function as a virtual function. There should no longer be the need for a switch statement or a type variable. Write a main function that creates a vector or array of pets that includes at least one bird, one dog, and one cat, and then loops through and outputs a description of each one.

cout << "Dog named " << m_name << endl; cout << "Neuter/Spayed: " << m_neutered << endl; } private: bool m_neutered; }; class Cat : public Pet { public: Cat(string name, bool neutered) : Pet...

void loginMenu() { cout << "请选择登录类型：" << endl; cout << "1. 学生登录" << endl; cout << "2. 管理员登录" << endl; cout << "3. 注册" << endl; cout << "0. 退出" << endl; 在不使用数据库的前提下，怎么将注册得到的信息用于登录、

outfile << user.username << " " << user.password << " " << user.email << endl; outfile.close(); cout << "注册成功！" << endl; } // 登录函数，从文件中读取用户信息进行校验 void loginUser() { string...

#include<iostream> #include<stdio.h> #include<malloc.h> using namespace std;//声明命名空间 //链栈 typedef struct stacknode{ int data;//数据域 struct stacknode next;//指针域 }stacknode,LinkStack; //初始化栈，创建一个空栈 void initLinkStack(LinkStack &L){ L=NULL;//空链站 } //判断栈是否为空 int emptyLinkStack(LinkStack L){ if(L==NULL){ return 0; }else{ return 1; } } //入栈 void pushLinkStack(LinkStack &L,int e){ LinkStack p; p=(LinkStack)malloc(sizeof(stacknode)); p->data=e; p->next=L; L=p; } //出栈 void popLinkStack(LinkStack &L,int &e){ LinkStack p; p=L; e=L->data;//取出栈顶元素给e L=L->next; delete(p); } //十进制转2、8、16进制，采用除基倒取余法 void numberConversionL(int oNumber,int cvNumber){ LinkStack L; //创建栈 int x; initLinkStack(L); //初始化栈 while(oNumber){ x=oNumber%cvNumber; pushLinkStack(L,x);//余数入栈 oNumber=oNumber/cvNumber; } //余数出栈 while(emptyLinkStack(L)){ popLinkStack(L,x); switch(x){ case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8: case 9:cout<<x; break; case 10:cout<<"A"; break; case 11:cout<<"B"; break; case 12:cout<<"C"; break; case 13:cout<<"D"; break; case 14:cout<<"E"; break; case 15:cout<<"F"; break; } } } //主函数 int main(){ int oNumber,cvNumber; int oNumberL,cvNumberL; int choose; cout<<"请选择所需功能\n1.使用链栈转换\n2.退出程序"; cout<<endl; //换行 cin>>choose; while(choose!=2){ switch(choose){ case 1:{ cout<<"请输入要转换的十进制数："<<endl; cin>>oNumberL; cout<<"请输入要转换至的进制，仅限输入2、8以及16："<<endl; cin>>cvNumberL; numberConversionL(oNumberL,cvNumberL); break; } default: cout<<"\n!!!您的选择不正确，请重新选择!!!\n"; } cout<<endl; //换行 cout<<"请选择所需功能\n1.使用链栈转换\n2.退出程序"; cout<<endl; //换行 cin>>choose; } return 0; }这段代码数制转换器的研究背景和意义

这段代码实现了一个数制转换器，可以将十进制数转换为二进制、八进制或十六进制。数制转换在计算机领域中非常重要，因为不同的进制可以用不同的位数来表示同一个数，而在计算机中，位数的变化会对数据的存储和处理...

实验四：线性结构的应用

cout<<"\n请输入第"<<i<<"项的指数："; cin>>e; s=new term; s->coef=a; s->exp=e; s->next=ah->next; ah->next=s; } return ah; } void print(polynom ah) { polynom p; p=ah->next; float a;int e; if...

进制转换(进行十进制与任意进制的转换）我的作业顺便发一下以供参考

cout<<"请输入你要转换的进制（大于0，小于36！）"<<endl; cin>>base; if(base<0||base>36) { cout<<"输入错误！请重新输入！"<<endl; } int n=0; while(sum!=0&&n<50) { b=sum*base; arr1[n]=b+'0';...

switch (n) { case 1: cout << "The number is 1" << endl; case 2: cout << "The number is 2" << endl; break; default: cout << "The number is not 1 or 2" << endl; }

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switch (n) { case 1: cout << "The number is 1" << endl; case 2: cout << "The number is 2" << endl; break; default: cout << "The number is not 1 or 2" << endl; }

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cout<<"Case #"<<(i+1)<<": false"<<endl;

void loginMenu() { cout << "请选择登录类型：" << endl; cout << "1. 学生登录" << endl; cout << "2. 管理员登录" << endl; cout << "3. 注册" << endl; cout << "0. 退出" << endl; 在不使用数据库的前提下，怎么将注册得到的信息用于登录、

实验四：线性结构的应用

进制转换(进行十进制与任意进制的转换）我的作业顺便发一下以供参考

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